Authorities haven’t given a motive for the latest violence, which left two firefighters dead and two other firefighters and an off-duty police officer from a nearby town wounded after they responded to the call of a fire.

And they can’t ask the shooter, who was found dead of a self-inflicted gunshot wound to the head around 11 a.m., about six hours after first calls about the fire came in.

Investigators believe the suspect, William Spengler, 62, set the original fire, then likely set himself up on a berm with a clear view of the scene and started shooting.

“It appears that it was a trap,” Webster Police Chief Gerald Pickering said. “There was a car and a house that were involved in flames, probably set by Mr. Spengler, who laid in wait in armament and then shot the first responders.”

In chilling audio heard over the scanner, a West Webster Fire Department firefighter reported “multiple firemen shot” – including himself, with wounds to his lower back and lower leg – and “shots still being fired.”

For several hours after that Monday, the threat of gunfire stopped firefighters from battling the blaze and forced police SWAT teams to evacuate 33 people in the neighborhood of small, waterfront homes.

Eventually, seven houses were “totally destroyed” by the fire. Although the fires were under control as of 2:30 p.m. ET, by then authorities still hadn’t been able to get in any of the homes. Pickering said it’s possible more victims could be inside.